[Dovecot] Mailbox directory permissions (LDA, 0600 -> 0660, virtual users)

[Marcin Hłybin]

Hello,

I have a quite common dovecot configuration with virtual users support:
1. User configuration is stored in MySQL database.
2. Mailboxes are owned by vmail:vmail with permission 0600 or 
drwx------.

Is it possible to change mailbox mode to 0660?

Dovecot version is 2.1.7
Part of SQL configuration:

user_query = \
	SELECT \
		CONCAT_WS('/', home, u.uid, d.domain_name, u.user_name) AS home, \
		500 AS uid, \
		500 AS gid \
	FROM users u \
		LEFT JOIN domains d ON u.domain_id = d.id \
	WHERE \
		u.user_name = '%n' AND \
		d.domain_name = '%d' AND \
		u.active = 1

Regards.

-- 
M.